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Contents

ix

5.4Algorithms of Linear Filtering and Extrapolation under Fixed Sample

Size of Measurements 156

5.4.1Optimal Parameter Estimation Algorithm by Maximal Likelihood

Criterion for Polynomial Target Track: A General Case...........

157

5.4.2Algorithms of Optimal Estimation of Linear Target Track

Parameters.........................................................................................

159

5.4.3Algorithm of Optimal Estimation of Second-Order Polynomial

Target Track Parameters

162

5.4.4 Algorithm of Extrapolation of Target Track Parameters..................

166

5.4.5Dynamic Errors of Target Track Parameter Estimation Using

Polar Coordinate System 168

5.5 Recurrent Filtering Algorithms of Undistorted Polynomial Target

 

Track Parameters

 

170

5.5.1

Optimal Filtering Algorithm Formula Flowchart.............................

170

5.5.2

Filtering of .....................................Linear Target Track Parameters

174

5.5.3

Stabilization ..........................Methods for Linear Recurrent Filters

177

 

5.5.3.1 Introduction of Additional Term into Correlation

 

 

..........................................

Matrix of Extrapolation Errors

178

 

5.5.3.2 .......Introduction of Artificial Aging of Measuring Errors

179

 

5.5.3.3 ............................................................

Gain Lower Bound

179

5.6 Adaptive Filtering ......Algorithms of Maneuvering Target Track Parameters

179

5.6.1

Principles of Designing the Filtering Algorithms

 

 

of Maneuvering Target Track Parameters

179

 

5.6.1.1 ...................................................................

First Approach

180

 

5.6.1.2 ...............................................................

Second Approach

181

 

5.6.1.3 .................................................................

Third Approach

181

5.6.2

Implementation of Mixed Coordinate Systems under Adaptive

 

 

Filtering.............................................................................................

 

181

5.6.3

Adaptive Filtering Algorithm Version Based on Bayesian

 

 

Approach in Maneuvering Target

186

5.7 Logical Flowchart ........of Complex Radar Signal Reprocessing Algorithm

192

5.8 Summary and Discussion...............................................................................

193

References.................................................................................................................

 

 

199

Chapter 6 Principles of Control Algorithm Design for Complex Radar System

 

Functioning at Dynamical ..............................................................................Mode

201

6.1 Configuration and ...........................Flowchart of Radar Control Subsystem

202

6.2 Direct Control of .............................Complex Radar Subsystem Parameters

207

6.2.1

Initial Conditions...............................................................................

207

6.2.2

Control under Directional Scan in Mode of Searched

 

 

New Targets...............................................................................

207

6.2.3

Control Process under Refreshment of Target in Target

 

 

Tracing Mode....................................................................................

211

6.3 Scan Control in New ................................................Target Searching Mode

213

6.3.1

Problem Statement .....and Criteria of Searching Control Optimality

213

6.3.2

Optimal Scanning ...........Control under Detection of Single Target

214

6.3.3

Optimal Scanning Control under Detection of Unknown

 

 

Number of .............................................................................Targets

215

6.3.4

Example of Scanning Control Algorithm in Complex Radar

 

Systems under Aerial Target Detection and Tracking 219

x

 

Contents

6.4

Power Resource Control under Target Tracking............................................

222

 

6.4.1 Control Problem Statement...............................................................

222

 

6.4.2 Example of Control Algorithm under Target Tracking Mode..........

223

 

6.4.3 Control of Energy Expenditure under Accuracy Aligning...............

226

6.5

Distribution of Power Resources of Complex Radar System under

 

 

Combination of Target Searching and Target Tracking Modes

228

6.6

Summary and Discussion...............................................................................

231

References.................................................................................................................

233

Part II  Design Principles of Computer System for Radar Digital Signal Processing and Control Algorithms

Chapter 7 Design Principles of Complex Algorithm Computational Process

 

in Radar Systems....................................................................................................

237

7.1

Design Considerations....................................................................................

237

 

7.1.1

Parallel General-Purpose Computers................................................

238

 

7.1.2

Custom-Designed Hardware.............................................................

239

7.2

Complex Algorithm Assignment....................................................................

241

 

7.2.1 Logical and Matrix Algorithm Flowcharts.......................................

241

 

7.2.2

Algorithm Graph Flowcharts............................................................

243

 

7.2.3 Use of Network Model for Complex Algorithm Analysis................

246

7.3

Evaluation of Work Content of Complex Digital Signal Processing

 

Algorithm Realization by Microprocessor Subsystems 249

7.3.1

Evaluation of Elementary Digital Signal Processing

 

 

Algorithm Work Content...................................................................

249

7.3.2

Definition of Complex Algorithm Work Content Using

 

 

Network Model..................................................................................

250

7.3.3

Evaluation of Complex Digital Signal Reprocessing Algorithm

 

 

Work Content in Radar System

252

7.4 Paralleling of Computational Process............................................................

257

7.4.1

Multilevel Graph of Complex Digital Signal Processing Algorithm......

257

7.4.2

Paralleling of Linear Recurrent Filtering Algorithm

 

 

Macro-Operations.............................................................................

263

7.4.3

Paralleling Principles of Complex Digital Signal Processing

 

 

Algorithm by Object Set

265

7.5 Summary and Discussion...............................................................................

267

References.................................................................................................................

 

271

Chapter 8 Design Principles of Digital Signal Processing Subsystems Employed

 

by a Complex Radar System.....................................................................................

273

8.1Structure and Main Engineering Data of Digital Signal Processing

Subsystems

273

8.1.1

Single-Computer Subsystem.............................................................

273

8.1.2

Multicomputer Subsystem.................................................................

276

8.1.3 Multimicroprocessor Subsystems for Digital Signal Processing......

278

8.1.4Microprocessor Subsystems for Digital Signal

Processing in Radar...........................................................................

280

Contents

xi

8.2 Requirements for Effective Speed of Operation............................................

282

8.2.1 Microprocessor Subsystem as a Queuing System.............................

282

8.2.2 Functioning Analysis of Single-Microprocessor Control

 

Subsystem as Queuing System 285

 

8.2.3 Specifications for Effective Speed of Microprocessor

 

 

Subsystem Operation.........................................................................

289

8.3

Requirements for RAM Size and Structure...................................................

293

8.4

Selection of Microprocessor for Designing the Microprocessor Subsystems......

295

8.5Structure and Elements of Digital Signal Processing and Complex

Radar System Control Microprocessor Subsystems 296

8.6High-Performance Centralized Microprocessor Subsystem for Digital

 

 

Signal Processing of Target Return Signals in Complex Radar Systems

299

 

8.7

Programmable Microprocessor for Digital Signal Preprocessing

 

 

 

of Target Return Signals in Complex Radar Systems

301

 

8.8

Summary and Discussion...............................................................................

302

 

References.................................................................................................................

 

306

Chapter 9

Digital Signal Processing Subsystem Design (Example)..........................................

309

 

9.1

General Statements.........................................................................................

309

 

9.2

Design of Digital Signal Processing and Control Subsystem Structure.........

310

 

 

9.2.1

Initial Statements...............................................................................

310

 

 

9.2.2

Main Problems of Digital Signal Processing

 

 

 

 

and Control Subsystem...................................................................

311

 

 

9.2.3

Central Computer System Structure for Signal Processing

 

 

 

 

and Control........................................................................................

314

 

9.3

Structure of Coherent Signal Preprocessing Microprocessor Subsystem......

315

 

9.4

Structure of Noncoherent Signal Preprocessing Microprocessor Subsystem.......

318

 

 

9.4.1

Noncoherent Signal Preprocessing Problems...................................

318

 

 

9.4.2

Noncoherent Signal Preprocessing Microprocessor Subsystem

 

 

 

 

Requirements.....................................................................................

321

 

9.5

Signal Reprocessing Microprocessor Subsystem Specifications....................

322

 

9.6

Structure of Digital Signal Processing Subsystem.........................................

325

 

9.7

Summary and Discussion...............................................................................

327

 

References.................................................................................................................

 

329

Chapter 10

Global Digital Signal Processing System Analysis...................................................

331

 

10.1

Digital Signal Processing System Design......................................................

331

 

 

10.1.1

Structure of Digital Signal Processing System.................................

331

 

 

10.1.2

Structure and Operation of Nontracking MTI..................................

332

 

 

10.1.3

MTI as Queuing System....................................................................

335

 

10.2

Analysis of “n – 1 – 1” MTI System..............................................................

339

 

 

10.2.1

Required Number of Memory Channels...........................................

339

 

 

10.2.2

Performance Analysis of Detector–Selector.....................................

340

 

 

10.2.3

Analysis of MTI Characteristics.......................................................

343

 

10.3

Analysis of “n n – 1” MTI System..............................................................

344

 

10.4

Analysis of “n m – 1” MTI System..............................................................

345

 

10.5

Comparative Analysis of Target Tracking Systems.......................................

347

 

10.6

Summary and Discussion...............................................................................

349

 

References.................................................................................................................

 

349

xii

 

Contents

Part III  Stochastic Processes Measuring in Radar Systems

 

Chapter 11 Main Statements of Statistical Estimation Theory...................................................

353

11.1

Main Definitions and Problem Statement......................................................

353

11.2

Point Estimate and Its Properties...................................................................

356

11.3

Effective Estimations.....................................................................................

358

11.4

Loss Function and Average Risk....................................................................

359

11.5

Bayesian Estimates for Various Loss Functions............................................

362

 

11.5.1

Simple Loss Function........................................................................

363

 

11.5.2 Linear Module Loss Function...........................................................

364

 

11.5.3

Quadratic Loss Function...................................................................

365

 

11.5.4

Rectangle Loss Function...................................................................

366

11.6

Summary and Discussion...............................................................................

366

References.................................................................................................................

 

368

Chapter 12 Estimation of Mathematical Expectation..................................................................

369

12.1

Conditional Functional...................................................................................

369

12.2

Maximum Likelihood Estimate of Mathematical Expectation.....................

373

12.3

Bayesian Estimate of Mathematical Expectation: Quadratic

 

 

Loss Function

381

 

12.3.1 Low Signal-to-Noise Ratio (ρ2 1).................................................

383

 

12.3.2 High Signal-to-Noise Ratio (ρ2 1).................................................

385

12.4

Applied Approaches to Estimate the Mathematical Expectation..................

386

12.5

Estimate of Mathematical Expectation at Stochastic Process Sampling.......

397

12.6

Mathematical Expectation Estimate under Stochastic Process

 

 

Amplitude Quantization

408

12.7

Optimal Estimate of Varying Mathematical Expectation of Gaussian

 

 

Stochastic Process

413

12.8

Varying Mathematical Expectation Estimate under Stochastic Process

 

 

Averaging in Time

422

12.9

Estimate of Mathematical Expectation by Iterative Methods........................

427

12.10

Estimate of Mathematical Expectation with Unknown Period......................

430

12.11

Summary and Discussion...............................................................................

436

References.................................................................................................................

 

439

Chapter 13 Estimation of Stochastic Process Variance...............................................................

441

13.1

Optimal Variance Estimate of Gaussian Stochastic Process.........................

441

13.2

Stochastic Process Variance Estimate under Averaging in Time..................

449

13.3

Errors under Stochastic Process Variance Estimate......................................

455

13.4

Estimate of Time-Varying Stochastic Process Variance................................

460

13.5

Measurement of Stochastic Process Variance in Noise.................................

468

 

13.5.1 Compensation Method of Variance Measurement............................

468

 

13.5.2

Method of Comparison.....................................................................

473

 

13.5.3 Correlation Method of Variance Measurement.................................

476

 

13.5.4 Modulation Method of Variance Measurement................................

478

13.6

Summary and Discussion...............................................................................

484

References.................................................................................................................

 

486

Contents

 

 

 

xiii

Chapter 14

Estimation of Probability Distribution and Density Functions

 

 

of Stochastic Process............................................................................................

487

 

14.1

Main Estimation Regularities........................................................................

487

 

14.2

Characteristics of Probability Distribution Function Estimate......................

491

 

14.3

Variance of Probability Distribution Function Estimate...............................

495

 

 

14.3.1

Gaussian Stochastic Process.............................................................

495

 

 

14.3.2

Rayleigh Stochastic Process..............................................................

499

 

14.4

Characteristics of the Probability Density Function Estimate.......................

504

 

14.5

Probability Density Function Estimate Based on Expansion in Series

 

 

 

Coefficient Estimations

509

 

14.6

Measurers of Probability Distribution and Density Functions:

 

 

 

Design Principles

514

 

14.7

Summary and Discussion...............................................................................

520

 

References.................................................................................................................

 

521

Chapter 15

Estimate of Stochastic Process Frequency-Time Parameters...................................

523

 

15.1

Estimate of Correlation Function...................................................................

523

 

15.2

Correlation Function Estimation Based on Its Expansion in Series...............

531

 

15.3

Optimal Estimation of Gaussian Stochastic Process Correlation

 

 

 

Function Parameter

539

 

15.4

Correlation Function Estimation Methods Based on Other Principles..........

554

 

15.5

Spectral Density Estimate of Stationary Stochastic Process.........................

561

 

15.6

Estimate of Stochastic Process Spike Parameters..........................................

570

 

 

15.6.1 Estimation of Spike Mean.................................................................

571

 

 

15.6.2 Estimation of Average Spike Duration and Average Interval

 

 

 

 

between Spikes..................................................................................

575

 

15.7

Mean-Square Frequency Estimate of Spectral Density.................................

579

 

15.8

Summary and Discussion...............................................................................

581

 

References.................................................................................................................

 

582

Preface

The essential task in radar systems is to find an appropriate solution to the problems related to robust signal processing and definition of signal parameters. There are now a number of books and papers published in journals devoted to signal processing in noise in radar systems, but many key issues remain unsolved. New approaches to these problems allow us not only to summarize investigations but also to derive better quality of robust signal processing in noise in radar systems.

This book addresses the problems of robust signal processing in complex radar systems (CRSs) based on the generalized approach to signal processing in noise. The generalized approach to signal processing in noise is proposed based on a seemingly abstract idea: the introduction of an additional noise source that does not carry any information about the signal to improve the qualitative performance of CRSs. Theoretical and experimental studies lead to the conclusion that the proposed generalized approach to signal processing in noise in CRSs allows formulating a decision-making rule based on the determination of the jointly sufficient statistics of the mean and variance of the likelihood function. The use of classical and modern signal processing approaches allows us to define only the sufficient statistic of the mean of the likelihood function (or functional).

The presence of additional information about the statistical characteristics of the likelihood function leads to better qualitative performances of robust signal processing in CRSs in comparison with optimal signal processing algorithms of classical and modern theories. The generalized approach to signal processing allows us to extend the well-known boundaries of potential noise immunity set up by classical and modern signal processing theories. The use of CRSs based on the generalized approach to signal processing in noise allows us to obtain better detection performances, particularly in comparison with CRSs constructed on the basis of optimal and asymptotic optimal signal processing algorithms of classical and modern signal processing theories.

To better understand the fundamental statements and concepts of the generalized approach, the reader is invited to consult my earlier books: Signal Processing in Noise: A New Methodology (IEC, Minsk, 1998), Signal Detection Theory (Springer-Verlag, New York, 2001), Signal Processing Noise

(CRC Press, Boca Raton, FL, 2002), and Signal and Image Processing in Navigational Systems

(CRC Press, Boca Raton, FL, 2005).

The radar system is an important element in the field of electrical engineering. In university engineering courses, in general, the emphasis is usually on the basic tools used by the electrical engineer, such as circuit design, signals, solid state, digital processing, electronic devices, electromagnetics, automatic control, microwaves, and so on. In the real world of electrical engineering practice, however, these are only techniques, piece parts, or subsystems that make up some type of system employed for a useful purpose.

There are various aspects to radar system design. However, before a new radar system can be manufactured, a conceptual design has to be made to guide the actual development, taking into consideration the requirements of the radar system that must be customerand user-friendly. Conceptual design involves identifying the characteristics of the radar system in accordance with the radar equation and related equations and the general characteristics of the subsystems such as transmitter, antenna, receiver, signal processing, etc., that might be used. A conceptual design cannot be formed without a systems approach. Another important procedure is to define the structure of computer subsystems used in the radar for the purpose of implementing modern robust signal processing algorithms.

It should be noted that there are at least two ways in which a new CRS might be produced. One method is based on exploiting the advantages of some new invention, new technique, new device, or new knowledge. The invention of the microwave magnetron early in World War II is an example.

xv

xvi

Preface

After the magnetron appeared, radar system design was different from what it had been before. The other, and probably more common, method for conceptual radar system design is to identify the function the new radar system has to perform, examine the various approaches available to achieve the desired capability, carefully evaluate each approach, and then select the one that best meets the needs within the operational and fiscal constraints imposed. This book discusses in detail these two methods that are based on a systems approach to design radar systems.

An important task in designing CRSs is to use robust signal processing algorithms and accurate definition of signal parameters. To this end, theory and methods of experimental investigations of stochastic processes are attracted to design the CRS. The theory of statistical estimates, for example, can be used for analyzing regularities to design and construct optimal and quasi-optimal meters of statistical parameters of stochastic processes. At the same time, significant attention is paid to investigation of systematic and random errors of statistical parameter definition as a function of considered time interval and noise level.

A detailed analysis of various procedures and methods to measure and estimate the main statistical parameters of stochastic processes, such as mean (or mathematical expectation), variance, correlation (covariance) function, power spectral density, probability density functions, spikes of energy spectra, etc., is presented. Analog and discrete procedures and methods for measurements and errors, which are characteristic of these procedures and methods, are investigated. In addition, structural block diagrams of digital meters are considered. Structural block diagrams of optimal meters to define the mathematical expectation (mean), variance, and parameters of the correlation (covariance) function are discussed. The variance of estimations and biases of the earlier-mentioned parameters is measured. A procedure to measure the mathematical expectation (mean) and variance of nonstationary stochastic process under robust signal processing used in CRSs is identified. General formulas for definition of biases and variances of statistical parameter estimations are also presented for direct analytical calculation.

I would like to thank my colleagues in the field of robust signal processing in radar systems for useful discussion about the main results, in particular, Professors V. Ignatov, A. Kolyada, I. Malevich, G. Manshin, D. Johnson, B. Bogner, Yu. Sedyshev, J. Schroeder, Yu. Shinakov, A. Kara, Kyung Tae Kim, Yong Deak Kim, Yong Ki Cho, V. Kuzkin, W. Uemura, Dr. O. Drummond, and others.

I would also like to express my gratitude to my colleagues from the Department of Information Technologies and Communications, Electronics Engineering School, College of IT Engineering, Kyungpook National University (KNU), Daegu, South Korea, for useful remarks and comments and their help in completing this project.

This research was supported by the Kyungpook National University Research Fund, 2010.

AlotofcreditisalsoduetoNoraKonopka,KariBudyk,RichardTressider,SuganthiThirunavukarasu, and John Gandour as well as to the entire staff at CRC Press, Taylor & Francis Group, for their encouragement and support.

Last, but definitely not least, I would like to thank my family—my lovely wife, Elena; my sons, Anton and Dima; and my dear mom, Natali—for putting up with me during the writing of the manuscript. Without their support, this book would not have been possible!

Finally, I wish to express my lifelong, heartfelt gratitude to Dr. Peter Tuzlukov, my father and teacher, who introduced me to science.

Vyacheslav Tuzlukov

Preface

xvii

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